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Fur Elise
Fur is a thick growth of hair that covers the skin of mammals. It consists of a combination of oily guard hair on top and thick underfur beneath. The guard hair keeps moisture from reaching the skin; the underfur acts as an insulating blanket that keeps the animal warm. The fur of mammals has many uses: protection, sensory purposes, waterproofing, and camouflaging, with the primary usage being thermoregulation. The types of hair include * ''definitive'', which may be shed after reaching a certain length; * ''vibrissae'', which are sensory hairs and are most commonly whiskers; * ''pelage'', which consists of guard hairs, under-fur, and awn hair; * '' spines'', which are a type of stiff guard hair used for defense in, for example, porcupines; * ''bristles'', which are long hairs usually used in visual signals, such as the mane of a lion; * ''velli'', often called "down fur", which insulates newborn mammals; and * ''wool'', which is long, soft, and often curly. Hair length ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Selection
Sexual selection is a mode of natural selection in which members of one biological sex mate choice, choose mates of the other sex to mating, mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex (intrasexual selection). These two forms of selection mean that some individuals have greater reproductive success than others within a population, for example because they are more Animal sexual behaviour, attractive or prefer more attractive partners to produce offspring. Successful males benefit from frequent mating and monopolizing access to one or more fertile females. Females can maximise the return on the energy they invest in reproduction by selecting and mating with the best males. The concept was first articulated by Charles Darwin who wrote of a "second agency" other than natural selection, in which competition between mate candidates could lead to speciation. The theory was given a mathematical basis by Ronald F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Dimorphism In Non-human Primates
Sexual dimorphism describes the morphological, physiological, and behavioral differences between males and females of the same species. Most primates are sexually dimorphic for different biological characteristics, such as body size, canine tooth size, craniofacial structure, skeletal dimensions, pelage color and markings, and vocalization. However, such sex differences are primarily limited to the anthropoid primates; most of the strepsirrhine primates (lemurs and lorises) and tarsiers are monomorphic. Sexual dimorphism can manifest itself in many different forms. In male and female primates there are obvious physical difference such as body size or canine size. Dimorphism can also be seen in skeletal features such as the shape of the pelvis or the robustness of the skeleton. There are two mating systems in the sexual selection of primates. Types Body size Extant primates exhibit a broad range of variation in sexual size dimorphism (SSD), or sexual divergence in body size.Dunham ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
